If you used Disk Utility, which is most likely, then you have to backup everything and reformat to get one partition. If that is a deal breaker, then just delete everything on the System 9 partition and use the space for storage. It will be somewhat inflexible and annoying, but that is the only choice I know of short of reformatting.

But it shouldn't be a problem because you have a full backup of your entire hard drive... right?!:bomb: